The Silver Species, now subordinate to humans, really started treating humans as their sovereigns.
But to have them personally brave dangers—that would be asking too much of them, so during this period, a significant number of the Silver Species' upper echelons have been petitioning and advising the Human Government. They expressed their hope to hand over their race's armies to humans, even their motherships, as long as they are allowed to remain within the Moon.
And naturally, all such petitions and advice were rejected.
Nonsense, what humans need is not just their warships, but also for these upper echelons to prove that humans have not driven them to extinction. Their very presence is fundamental to the snowball effect; only when they come forward to speak, can more of the Silver Species gather around humans. Thus, they must go willingly or unwillingly.